.Net Com+ DLL in VB6 - RegFree

[ThiagoPSanches]

I would like to hear your opinion/information about using a .Net Com+ DLL in VB6 without registration.

This would be the DLL:
https://www.easyxls.com/component-excel-library

This DLL requires registration with the "regsvcs" file.

I tried many things described here in the forum (Manifest / SxS) a while ago, but I was unsuccessful... I'm starting to see this again...

Thanks,
Thiago

[rjsnipe]

Just to clarify, is this a .net app and that dll is vb6?

[rjsnipe]

Looking on their site it looks like they have a .net version. Why can't you use that?

[Arnoutdv]

It's the other way around.
The application is VB6 and the DLL is .net

[ThiagoPSanches]

Exactly: The application is written in VB6, and the DLL is a .NET assembly.

The component we have is the COM+ version (not a regular .NET class library), and it was specifically designed for VB6 interoperability.

However, the issue we're facing with regfree usage seems to be related to the fact that this is a COM+ component, not a traditional COM DLL.

[wqweto]

> However, the issue we're facing with regfree usage seems to be related to the fact that this is a COM+ component, not a traditional COM DLL.

You have to explain these "issues" in depth. There is not that much difference between "COM+ component" and "traditional COM DLL" besides activation and transaction participation.

One is out-of-process (COM+) using a surrogate host process so regfree activation is out of the question. This sounds like an "insurmountable issue" but I might be missing something with COM+ activation you are using.

cheers,
</wqw>

[ThiagoPSanches]

Hi wqweto,

I'm trying to make it work using a manifest file, based on examples I found in forum and online.

I've tested a few variations like this one:

<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
<assembly xmlns="urn:schemas-microsoft-com:asm.v1" manifestVersion="1.0">
  <assemblyIdentity type="win32" name="Project1" version="1.0.0.0" />

  <!-- Dependency on .NET CLR -->
  <dependency>
    <dependentAssembly>
      <assemblyIdentity
        name="clr"
        version="4.0.30319.0"
        publicKeyToken="b77a5c561934e089"
        processorArchitecture="x86" />
    </dependentAssembly>
  </dependency>

  <!-- Common controls -->
  <dependency>
    <dependentAssembly>
      <assemblyIdentity
        type="win32"
        name="Microsoft.Windows.Common-Controls"
        version="6.0.0.0"
        processorArchitecture="X86"
        publicKeyToken="6595b64144ccf1df"
        language="*" />
    </dependentAssembly>
  </dependency>

  <!-- EasyXLS .NET COM Interop -->
  <file name="EasyXLS.dll">
    <comClass
      clsid="{ED783240-17F3-3709-96DE-93DCA09DB1BF}"
      progid="EasyXLS.ExcelDocument"
      threadingModel="Apartment" />
  </file>
</assembly>

Also, here's the VB6 code I'm using to test the activation:

Private Type tagInitCommonControlsEx
   lngSize As Long
   lngICC As Long
End Type
Private Declare Function InitCommonControlsEx Lib "comctl32.dll" (iccex As tagInitCommonControlsEx) As Boolean

Public Sub Main()
   Dim iccex As tagInitCommonControlsEx

   With iccex
      .lngSize = LenB(iccex)
      .lngICC = &H200 ' ICC_USEREX_CLASSES
   End With

   On Error Resume Next
   InitCommonControlsEx iccex
   On Error GoTo 0

   ' Test
   Dim a As Object
   Set a = CreateObject("EasyXLS.ExcelDocument")
   MsgBox Not a Is Nothing
End Sub

But I get the following error messages when running the test:

The application has failed to start because its side-by-side configuration is incorrect.
OR
ActiveX component can't create object

[rjsnipe]

create a build output folder with Project.exe, EasyXLS.dll and this file

Project1.manifest

<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
<assembly
    xmlns="urn:schemas-microsoft-com:asm.v1" manifestVersion="1.0">
    <assemblyIdentity type="win32" name="Project1" version="1.0.0.0" />
    <dependency>
        <dependentAssembly>
            <assemblyIdentity name="EasyXLS" publicKeyToken="632c31013494909a" version="9.1.0.0" processorArchitecture="msil" />
        </dependentAssembly>
    </dependency>
</assembly>

Then run this

& mt -nologo -manifest Project1.manifest -outputresource:Project1.exe;#1

Add the below the the manifest only if you want it to be able to pick up modern windows themes

<!-- Common controls -->
    <dependency>
        <dependentAssembly>
            <assemblyIdentity
        type="win32"
        name="Microsoft.Windows.Common-Controls"
        version="6.0.0.0"
        processorArchitecture="X86"
        publicKeyToken="6595b64144ccf1df"
        language="*" />
        </dependentAssembly>
    </dependency>

[wqweto]

I was suspecting there is no COM+ in sight, neither in manifest nor in code.

Try dependentAssembly tag as already suggested. This is the way to "reference" the manifest embedded in the .Net DLL.

Btw, I'm not sure if these DLL manifests are automatically generated on build for COM interop classes but there is a way to recreate and embed these with mt.exe

cheers,
</wqw>

[ThiagoPSanches]

Hi rjsnipe and wqweto,

Thank you both for your input.

I generated the Project1.manifest as follows:

<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
<assembly
    xmlns="urn:schemas-microsoft-com:asm.v1" manifestVersion="1.0">
    <assemblyIdentity type="win32" name="Project1" version="1.0.0.0" />
    <dependency>
        <dependentAssembly>
            <assemblyIdentity name="EasyXLS" publicKeyToken="632c31013494909a" version="9.0.0.0" processorArchitecture="msil" />
        </dependentAssembly>
    </dependency>
</assembly>

VB6 App (Project1.exe):

Public Sub Main()
   Dim a As Object
   
   MsgBox "Start"
   
   Set a = CreateObject("EasyXLS.ExcelDocument")
   MsgBox Not a Is Nothing
End Sub

I then ran:

mt -nologo -manifest Project1.manifest -outputresource:Project1.exe;#1

However, when executing the app, I get the following error:
“The application has failed to start because its side-by-side configuration is incorrect.”
( The error occurs immediately — the initial "Start" message box doesn't even appear )

I was suspecting there is no COM+ in sight, neither in manifest nor in code.

Try dependentAssembly tag as already suggested. This is the way to "reference" the manifest embedded in the .Net DLL.

Btw, I'm not sure if these DLL manifests are automatically generated on build for COM interop classes but there is a way to recreate and embed these with mt.exe

cheers,
</wqw>

Just to clarify, the company behind EasyXLS refers to this version of the DLL as “COM+”:
https://www.easyxls.com/component-excel-library

And we use regsvcs.exe to register the assembly, as described here:
https://www.easyxls.com/manual/troub...ct-failed.html
( I’ve always registered components using regsvr32 )

[ThiagoPSanches]

Adding type="win32" to the manifest fixed the side-by-side activation issue.
Here's the updated Project1.manifest:

<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
<assembly xmlns="urn:schemas-microsoft-com:asm.v1" manifestVersion="1.0">
    <assemblyIdentity type="win32" name="Project1" version="1.0.0.0" />
    
    <dependency>
        <dependentAssembly>
            <assemblyIdentity 
                name="EasyXLS" 
                publicKeyToken="632c31013494909a" 
                version="9.0.0.0" 
                processorArchitecture="msil"
                type="win32" />
        </dependentAssembly>
    </dependency>
</assembly>

Now the application starts, but I'm getting this error:

"Run-time error '429': ActiveX component can't create object"

[wqweto]

> And we use regsvcs.exe to register the assembly, as described here:

Oh, so it's some .Net development I'm not qualified to comment on.

I highly doubt you'll be able to use regfree activation with this component if it's registered under COM+. I would first try running it as normal in-proc COM server as it's hard to fathom what gains using it under COM+ from a *single* threaded evironment like VB6 are expected.

Btw, another remote option is that you might be able to manually simulate what COM+ does by (manually) running dllhost.exe (or whatever) with just the right parameters so that it hosts your DLL and registers it's class factories in ROT but I've never done this or heard anyone here doing it.

cheers,
</wqw>

[ThiagoPSanches]

> And we use regsvcs.exe to register the assembly, as described here:

Oh, so it's some .Net development I'm not qualified to comment on.

I highly doubt you'll be able to use regfree activation with this component if it's registered under COM+. I would first try running it as normal in-proc COM server as it's hard to fathom what gains using it under COM+ from a *single* threaded evironment like VB6 are expected.

Btw, another remote option is that you might be able to manually simulate what COM+ does by (manually) running dllhost.exe (or whatever) with just the right parameters so that it hosts your DLL and registers it's class factories in ROT but I've never done this or heard anyone here doing it.

cheers,
</wqw>

Thanks anyway, wqweto — I really appreciate your time and input.

[rjsnipe]

It looks like just a normal .net com dll.

Can you confirm the line in your code that throws the error?

[rjsnipe]

When i say looks like, what i mean is, it is a normal .net framework com dll. It does not use regsvr32 to register, it uses regasm, that supplied RegSvcs.exe must be made by them to do the registration and likely just calls regasm. Which is totally confusing.

You might need to generate a manifest as wqweto said. run this

& mt -nologo -managedassemblyname:EasyXLS.dll -nodependency -out:EasyXLS.manifest

which is likely enough if it's all deployed in the same folder, you could embed it but it's a signed assembly and it will complain. So in the deployment you would need
Project1.exe
EasyXLS.dll
EasyXLS.manifest

[rjsnipe]

also i notice you use CreateObject. Add the supplied tlb to the project references and then you can strongly type the usage

[Joe Caverly]

that supplied RegSvcs.exe must be made by them to do the registration and likely just calls regasm.

RegSvcs.exe is a Microsoft utility.

C:\...\v4.0.30319>regsvcs.exe
Microsoft (R) .NET Framework Services Installation Utility Version 4.8.9037.0
Copyright (C) Microsoft Corporation.  All rights reserved.

USAGE: regsvcs.exe [options] AssemblyName
Options:
    /? or /help     Display this usage message.
    /fc             Find or create target application (default).
    /c              Create target application, error if it already exists.
    /exapp          Expect an existing application.
    /tlb:<tlbfile>  Filename for the exported type library.
    /appname:<name> Use the specified name for the target application.
    /parname:<name> Use the specified name or id for the target partition.
    /extlb          Use an existing type library.
    /reconfig       Reconfigure existing target application (default).
    /noreconfig     Don't reconfigure existing target application.
    /u              Uninstall target application.
    /nologo         Suppress logo output.
    /quiet          Suppress logo output and success output.
    /componly       Configure components only, no methods or interfaces.
    /appdir:<path>  Set application root directory to specified path.

Joe

[rjsnipe]

ah i see, my bad. I didn't realise there was a separate .net exe for registering but see now it's for com+ .net.

If the classes you want to use are deigned to be used in process you should be fine but that depends how they have written it. Can you give an example of the usage of the library?

[rjsnipe]

Just to bring it all together.
If you do the 2 things i detail above it will work with registration free com (I've tested it), however depending on the implementation details of the dll it might not actually do what you need it to if it needs some com+ infrastructure but as wqweto said "it's hard to fathom what gains using it under COM+" so your chances are good. They also have a non com+ dll so if you were really commited to the goal and this does not work, then you could wrap that with your own vanilla com classes for just the bits you need, or more likely just minimise the calls you actually need to do in vb6 and do most of it in .net

[rjsnipe]

Just to bring it all together.
If you do the 2 things i detail above it will work with registration free com (I've tested it), however depending on the implementation details of the dll it might not actually do what you need it to if it needs some com+ infrastructure but as wqweto said "it's hard to fathom what gains using it under COM+" so your chances are good. They also have a non com+ dll so if you were really commited to the goal and this does not work, then you could wrap that with your own vanilla com classes for just the bits you need, or more likely just minimise the calls you actually need to do in vb6 and do most of it in .net